调用时由调用函数的参数传入// std::placeholders::_2:不定参数2,调用时由调用函数的参数传入// std::placeholders::_3:不定参数3,调用时由调用函数的参数传入#defineCC_CALLBACK_0(__selector__,__target__,
target_type()if(func1.target_type() ==typeid(void(*)())) { std::cout <<"func1 targets a free function"<< std::endl; }target()auto* lambda = func2.target<decltype([](inta,intb) {returna + b; })>();if(lambda) { std::cout <<"func2 targets a lambda expression"<< std:...
在这个例子中,我们首先创建了一个std::function<void(int)>对象func,并将其绑定到函数myFunction。然后,我们使用func.target<void(*)(int)>()尝试提取函数指针。如果提取成功,我们通过该指针调用函数;否则,输出一条消息说明std::function没有持有函数指针。
问std::function.target返回空ENautofunction=std::function<CurlCallback>(std::bind(&NetworkResource:...
复制和移动：std::function对象可以被复制和移动,类似于其他C++对象.类型查询：可以通过成员函数 target_...
(__selector__,__target__, ...)std::bind(&__selector__,__target__,std::placeholders::_1,std::placeholders::_2, ##__VA_ARGS__)#defineCC_CALLBACK_3(__selector__,__target__, ...)std::bind(&__selector__,__target__,std::placeholders::_1,std::placeholders::_2,std::...
Instances of std::function can store, copy, and invoke any CopyConstructible Callable target–functions, lambda expressions, bind expressions, or other function objects, as well as pointers to member functions and pointers to data members std::function 是一个函数包装器模板,一个 std::function 类...
(__selector__,__target__, ...) std::bind(&__selector__,__target__, std::placeholders::_1, std::placeholders::_2, ##__VA_ARGS__)5 #define CC_CALLBACK_3(__selector__,__target__, ...) std::bind(&__selector__,__target__, std::placeholders::_1, std::placeholders:...
A decay copy of the wrapped callable object is stored internally by the object, which becomes the function’s target. The specific type of this target callable object is not needed in order to instantiate the function wrapper class; only its call signature. ...
#include "iostream" #include #include using namespace std; class Root { private: typedef std::function print_func; print_func F_print; publi